Extragalactic detections (as collected in the
Cologne Database)
are linked to galaxy
images added below the dates of the initial reports.

NOTES: (1) Molecules are ordered by first year of reported discovery, though some identifications
required confirmation by subsequent observations. (2) Identifications explicitly considered to be
tentative are indicated with italics; recent detections are implicitly tentative. (3) Detections
currently under dispute are indicated with an asterisk and orange text.
(4) 20 March 2017—In trying to decide how to categorize the 2015 optical/infrared detection of CrO,
it appears to have been found in cooler (~300 K) outflow material from the stellar-merger remnant V1309
Scorpii, not in a stellar atmosphere (though some of the other molecular bands reported by Kamiński
et al. are associated with much higher temperatures); the nature of
red novae are still being debated
by the community.

I'm still thinking about how to handle the situation this species
raises. When is a conformer distinct enough to have its own entry? Given the energy differences and the barrier
protecting the tran and cis isomers, this one probably is...